Linear compressor

ABSTRACT

Disclosed herein is a linear compressor having a shock-absorbing member interposed between a cylinder and an inner core. The shock-absorbing member acts to absorb external force generated when the inner core is press fitted around the cylinder, thereby preventing deformation of the cylinder.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a linear compressor and, more particularly, to a linear compressor in which a shock-absorbing member is interposed between a cylinder and an inner core to allow the inner core to be press fitted around the cylinder under shock absorbing operation thereof.

2. Description of the Related Art

Generally, a linear compressor is an apparatus to introduce, compress, and discharge operating fluid while linearly reciprocating a piston inside a cylinder using a linear driving force from a linear motor.

FIG. 1 is a longitudinal sectional view of a conventional linear compressor.

As shown in FIG. 1, the conventional linear compressor includes a hermetic container 2 to and from which operating fluid is introduced and discharged, and a compression unit mounted in the hermetic container 2 and adapted to compress the operating fluid.

The compression unit includes a cylinder 10 configured to receive the operating fluid from a fluid suction pipe 4 provided at the hermetic container 2, a piston 12 mounted to be linearly reciprocated in the cylinder 10 to thereby compress the operating fluid in the cylinder 10, and a linear motor 20 to reciprocate the piston 12.

To the cylinder 10 is coupled a discharge unit 16 including a discharge valve 16′. The discharge valve 16′ serves to discharge the operating fluid, compressed in the cylinder 10, into a fluid discharge pipe 6 provided at the hermetic container 2.

The piston 12 is internally formed with an operating fluid passage 12′ to guide the operating fluid from the fluid suction pipe 4 into the cylinder 10. A suction valve 18 is coupled to one end of the piston 12 located in the cylinder 10 to open or close the operating fluid passage 12′.

The linear motor 20 is generally divided into a stator, and a mover to electromagnetically interact with the stator to thereby be linearly reciprocated.

The stator includes an inner core 21 press fitted around the cylinder 10, a ring-shaped outer core 22 located around the inner core 21, and a coil 23 provided in the outer core 22 to produce a magnetic field.

As shown in FIG. 2, the inner core 21 is conventionally press fitted around the cylinder 10 using a hydraulic press during assembly of the linear motor 20.

The mover includes a magnet 25 located between the inner core 21 and the outer core 22, and a magnet frame 26 to connect the magnet 25 to the piston 12.

The compression unit is provided between a cylinder block 30 and a back cover 32 mounted in opposite sides of the hermetic container 2. Both the cylinder block 30 and the back cover 32 are supported by means of dampers 34.

Now, the operation of the conventional linear compressor configured as stated above will be explained in detail.

If electric power is applied to the linear motor 20, the piston 12 is reciprocated in the cylinder 10 using a reciprocation driving force from the linear motor 20. According to the reciprocating movement of the piston 12, the discharge valve 16′ and the suction valve 18 are repeatedly opened or closed.

Thereby, the operating fluid is introduced into the cylinder 10 through the fluid suction pipe 4 and the operating fluid passage 12′ defined in the piston 12 in succession, thereby being compressed in the cylinder 10 by the piston 12 have a high pressure. Finally, the compressed high-pressure operating fluid is discharged from the cylinder 10 by way of the discharge unit 16, and consequently, is discharged out of the hermetic container 2 through the fluid discharge pipe 6.

The introduction, compression, and discharge of the operating fluid as stated above are continuously repeated in that order so long as the linear motor 20 is driven.

However, the conventional linear compressor as stated above has a problem in that the cylinder 10 may be deformed when the inner core 21 is press fitted around the cylinder 10. This excessively increases frictional loss between the cylinder 10 and the piston 12, causing deterioration in the operational efficiency and durability as well as malfunction of the compressor.

SUMMARY OF THE INVENTION

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a linear compressor capable of preventing deformation of a cylinder when an inner core is press fitted around the cylinder during assembly.

In accordance with a first aspect of the present invention, the above and other objects can be accomplished by the provision of a linear compressor comprising: a cylinder containing a piston to be reciprocably mounted therein; a linear motor having an inner core fitted around the cylinder, the linear motor being connected to the piston; and a shock-absorbing member interposed between the cylinder and the inner core.

Preferably, the inner core may have an inner radius larger than an outer radius of the cylinder, but smaller than a radial distance between a center of the cylinder and the shock-absorbing member mounted around the cylinder, the radial distance being measured prior to fitting the inner core around the cylinder.

Preferably, the shock-absorbing member may include a plurality of shock-absorbing protrusions protruding from an outer circumferential wall of the cylinder toward the inner core.

Preferably, the plurality of shock-absorbing protrusions may be arranged in an axial direction of the cylinder.

Preferably, the plurality of shock-absorbing protrusions may be arranged in a circumferential direction of the cylinder.

Preferably, the shock-absorbing protrusions may have a ring shape.

Preferably, the shock-absorbing protrusions may extend outward from the outer circumferential wall of the cylinder.

Preferably, the shock-absorbing protrusions may be gradually tapered from the cylinder toward the inner core.

Preferably, each of the shock-absorbing protrusions may have a distal end pointed toward the inner core.

Preferably, the shock-absorbing member may be located at only part of an outer circumferential wall of the cylinder in an axial direction of the cylinder.

In accordance with a second aspect of the present invention, the above and other objects can be accomplished by the provision of a linear compressor comprising: a cylinder containing a piston to be reciprocably mounted therein and having a plurality of deformable shock-absorbing protrusions formed at an outer circumferential wall thereof; and a linear motor having an inner core fitted around the cylinder, the linear motor being connected to the piston, wherein the inner core may have an inner radius larger than an outer radius of the cylinder to be press fitted around the cylinder, but smaller than a radial distance between a center of the cylinder and the shock-absorbing member mounted around the cylinder, the radial distance being measured prior to fitting the inner core around the cylinder.

Preferably, the plurality of shock-absorbing protrusions may be arranged in an axial direction of the cylinder.

Preferably, the plurality of shock-absorbing protrusions may be arranged in a circumferential direction of the cylinder.

Preferably, the shock-absorbing protrusions may have a ring shape.

Preferably, the shock-absorbing protrusions may extend outward from the outer circumferential wall of the cylinder.

Preferably, the shock-absorbing protrusions may be gradually tapered from the cylinder toward the inner core.

Preferably, each of the shock-absorbing protrusions may have a distal end pointed toward the inner core.

In accordance with a third aspect of the present invention, the above and other objects can be accomplished by the provision of a linear compressor comprising: a cylinder arranged in a hermetic container, the interior of the cylinder being filled with operating fluid; a piston to compress the operating fluid in the cylinder while being reciprocated in the cylinder; a stator having an inner core press fitted around the cylinder, an outer core located around the inner core, and a coil provided in the outer core; and a mover located between the inner core and the outer core and connected to the piston to be reciprocated along with the piston as it interacts with the stator, wherein a plurality of shock-absorbing protrusions may protrude from an outer circumferential wall of the cylinder toward the inner core to be deformed as the inner core is press fitted around the cylinder.

Preferably, the shock-absorbing protrusions may extend outward from the outer circumferential wall of the cylinder.

Preferably, the shock-absorbing protrusions may be gradually tapered from the cylinder toward the inner core.

With the linear compressor of the present invention configured as stated above, external force generated when the inner core is press fitted around the inner core can be effectively absorbed by the shock-absorbing member interposed between the cylinder and the inner core.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view illustrating a conventional linear compressor;

FIG. 2 is an enlarged sectional view illustrating the assembled structure of a cylinder and an inner core of the conventional linear compressor;

FIG. 3 is a longitudinal sectional view illustrating a linear compressor according to the present invention;

FIG. 4 is an enlarged sectional view illustrating a cylinder and an inner core of the linear compressor according to the present invention, prior to being assembled; and

FIG. 5 is an enlarged sectional view illustrating the assembled structure of the cylinder and the inner core of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now, a linear compressor according to the present invention will be described with reference to the accompanying drawings.

For reference, there may be provided several preferred embodiments of the linear compressor according to the present invention, and hereinafter, the most preferred embodiment will be explained. The basic structure of the linear compressor is identical to the above described prior art, and thus, a detailed description thereof will be omitted.

FIG. 3 is a longitudinal sectional view illustrating a linear compressor according to the present invention.

As shown in FIG. 3, the linear compressor of the present invention comprises a hermetic container 50 forming the outer appearance of the compressor, a cylinder block 60 arranged in the hermetic container 50 at one side thereof, a back cover 62 arranged in the hermetic container 50 at the other side thereof, and a compression unit provided between the back cover 62 and the cylinder block 60 and adapted to compress operating fluid.

The hermetic container 50 is divided into a lower container 52 having an open upper surface, and an upper cover 54 to cover the upper surface of the lower container 52.

The hermetic container 50 is provided with a fluid suction pipe 56 to introduce exterior operating fluid into the hermetic container 50, and a fluid discharge pipe 58 connected to a discharge unit 80 to discharge compressed operating fluid to the outside of the hermetic container 50.

The back cover 62 has a fluid suction channel 62′ aligned to be connected to the fluid suction pipe 56.

Both the cylinder block 60 and the back cover 62 are supported by means of dampers 64 that utilize the elasticity of springs.

The compression unit includes a cylinder 70 mounted in the cylinder block 60, through which the operating fluid being introduced and discharged, and a piston 72 mounted to be linearly reciprocated in the cylinder 70 to thereby compress the operating fluid in the cylinder 70.

The cylinder 70 has an elongated hollow cylindrical shape open at opposite ends thereof. With this configuration, the piston 72 is inserted into the cylinder 70 through one of the open ends of the cylinder 70, i.e. through the left end as seen in FIG. 3, while the compressed operating fluid is discharged from the cylinder 70 through the other end, i.e. through the right end as seen in FIG. 3.

The discharge unit 80 is provided at the right end of the cylinder 70 to discharge the compressed operating fluid from the cylinder 70 into the fluid discharge pipe 58.

The discharge unit 80 includes a discharge cover assembly 82 configured to cover the right end of the cylinder 70 and connected to the fluid discharge pipe 58, and a discharge valve 84 mounted in the discharge cover assembly 82 to open or close the right end of the cylinder 70.

The discharge cover assembly 82 consists of an inner discharge cover 81 coupled to the cylinder 70, and an outer discharge cover 83 located around the inner discharge cover 81 and connected to the fluid discharge pipe 58.

The inner discharge cover 81 is formed with a fluid hole 81′ to communicate the interior of the inner discharge cover 81 with the interior of the outer discharge cover 83.

The discharge valve 84 includes a discharge valve body 85 located at the right end of the cylinder 70 in a horizontally movable manner, and a discharge valve spring 86 located between the discharge valve body 85 and the inner discharge cover 81 to elastically support the discharge valve body 85.

The piston 72 is internally formed with a fluid passage 72′, which communicates with the fluid suction channel 62′ of the back cover 62 and the interior of the cylinder 70 to guide the operating fluid therethrough. A suction valve 73 is mounted at an end of the piston 72 located in the cylinder 70 to open or close the fluid passage 72′.

The suction valve 73 performs opening and closing operations while being elastically deformed by a pressure difference between the fluid passage 72′ of the piston 72 and the interior of the cylinder 70.

Meanwhile, the compression unit further includes a linear motor 90 connected to the piston 72 to reciprocate the piston 72.

The linear motor 90 includes a mover connected to the piston 72, and a stator to electromagnetically interact with the mover to linearly reciprocate the mover along with the piston 72.

The mover includes a magnet 92 radially located around the cylinder 70 to be reciprocated in the stator, and a magnet frame 94 to connect the magnet 92 to the piston 72.

The stator includes a ring-shaped outer core 95 radially located around the cylinder 70 to be mounted between the cylinder block 60 and the back cover 62, a coil 96 provided in the outer core 95 to produce a magnetic field, and an inner core 98 inwardly spaced apart from the outer core 95.

The mover is located between the outer core 95 and the inner core 98.

The inner core 98 has a ring shape suitable to be mounted around the cylinder 70. Thereby, the inner core 98 is press fitted around the cylinder 70.

In particular, the inner core 98 is sized to be press fitted around the cylinder 70 while interposing a shock-absorbing member 100, which will be explained hereinafter, between the inner core 98 and the cylinder 70.

Preferably, the inner core 98 has an inner radius 98R larger than an outer radius 70R of the cylinder 70, but smaller than a radial distance 100L between a center of the cylinder 70 and the shock-absorbing member 100 mounted around the cylinder 70.

Here, the radial distance 100L is a value measured prior to press fitting the inner core 98 around the cylinder 70.

The shock-absorbing member 100 is mounted around the cylinder 70 so that it is interposed between the inner core 98 and the cylinder 70 when the inner core 98 is press fitted around the cylinder 70. The shock-absorbing member 100 has a deformable structure suitable to absorb external force caused during the press fitting of the inner core 98 around the cylinder 70.

In an embodiment of the present invention, the shock-absorbing member 100 may have shock-absorbing protrusions 100′ radially protruding from an outer circumferential wall of the cylinder 70 to face an inner circumferential wall of the inner core 98 when the inner core 98 is press fitted around the cylinder 70. In this case, each of the shock-absorbing protrusions 100′ may have a ring shape.

Alternatively, the plurality of shock-absorbing protrusions may be distributed in a circumferential direction of the cylinder 70.

The plurality of shock-absorbing protrusion 100′ may be arranged in an axial direction of the cylinder 70. Preferably, the plurality of shock-absorbing protrusions 100′ have uniform arrangement in the axial direction of the cylinder 70.

To prevent movement and separation of the inner core 98 after the inner core 98 is press fitted around the cylinder 70. the respective shock-absorbing protrusions 100′ may extend outward from the outer circumferential wall of the cylinder 70.

Also, the shock-absorbing protrusions 100′ are gradually tapered from the cylinder 70 toward the inner core 98. This tapered configuration effectively reduces generation of friction between the shock-absorbing protrusion 100′ and the inner core 98 when the inner core 98 is press fitted around the cylinder 70.

For example, each of the shock-absorbing protrusions 100′ may have a triangular cross section that is pointed toward the inner core 98.

The shock-absorbing member 100 as stated above may be integrally formed with the cylinder 70, or may be formed as a deformable separate member to be mounted to the outer circumferential wall of the cylinder 70.

If necessary, the shock-absorbing member 100 may be provided at only part of the outer circumferential wall of the cylinder 70 in the axial direction of the cylinder 70.

Now, the operation and effects of the linear compressor according to the present invention configured as stated above will be explained.

Upon driving of the linear motor 90, the piston 72 is continuously reciprocated in the cylinder 70 using a driving force from the linear motor 90, thereby allowing introduction, compression, and discharge of the operating fluid through the cylinder 70 to be repeatedly performed.

In this case, since the cylinder 70 is assembled to eliminate the risk of deformation thereof through the use of the shock-absorbing member 100, the piston 72 is able to be smoothly reciprocated in the cylinder 70.

As is apparent from the above description, a linear compressor according to the present invention has the following effects.

Firstly, according to the present invention, a shock-absorbing member operates to absorb external force generated when an inner core is press fitted around a cylinder upon assembly, allowing the cylinder to keep its original inner diameter determined upon molding thereof. This has the effect of preventing deterioration of operational efficiency due to the deformation of the cylinder, and achieving improved durability and reduced operational malfunction.

Secondly, according to the present invention, the shock-absorbing member includes a plurality of shock-absorbing protrusions outwardly protruding from the outer circumferential wall of the cylinder. These outwardly protruding shock-absorbing protrusions effectively prevent movement and separation of the inner core, ensuring stable driving of a linear motor.

Thirdly, each of the shock-absorbing protrusions has a distal end pointed toward the inner core. This configuration minimizes generation of friction between the inner core and the shock-absorbing member when the inner core is press fitted around the cylinder. As a result, the inner core can be more easily press fitted around the cylinder and is substantially not effected by external force.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. 

1. A linear compressor comprising: a cylinder containing a piston to be reciprocably mounted therein; a linear motor having an inner core fitted around the cylinder, the linear motor being connected to the piston; and a shock-absorbing member interposed between the cylinder and the inner core.
 2. The compressor as set forth in claim 1, wherein the inner core has an inner radius larger than an outer radius of the cylinder, but smaller than a radial distance between a center of the cylinder and the shock-absorbing member mounted around the cylinder, the radial distance being measured prior to fitting the inner core around the cylinder.
 3. The compressor as set forth in claim 1, wherein the shock-absorbing member includes a plurality of shock-absorbing protrusions protruding from an outer circumferential wall of the cylinder toward the inner core.
 4. The compressor as set forth in claim 3, wherein the plurality of shock-absorbing protrusions are arranged in an axial direction of the cylinder.
 5. The compressor as set forth in claim 3, wherein the plurality of shock-absorbing protrusions are arranged in a circumferential direction of the cylinder.
 6. The compressor as set forth in claim 3, wherein the shock-absorbing protrusions have a ring shape.
 7. The compressor as set forth in claim 3, wherein the shock-absorbing protrusions extend outward from the outer circumferential wall of the cylinder.
 8. The compressor as set forth in claim 3, wherein the shock-absorbing protrusions are gradually tapered from the cylinder toward the inner core.
 9. The compressor as set forth in claim 8, wherein each of the shock-absorbing protrusions has a distal end pointed toward the inner core.
 10. The compressor as set forth in claim 1, wherein the shock-absorbing member is located at only part of an outer circumferential wall of the cylinder in an axial direction of the cylinder.
 11. A linear compressor comprising: a cylinder containing a piston to be reciprocably mounted therein and having a plurality of deformable shock-absorbing protrusions formed at an outer circumferential wall thereof; and a linear motor having an inner core fitted around the cylinder, the linear motor being connected to the piston, wherein the inner core has an inner radius larger than an outer radius of the cylinder to be press fitted around the cylinder, but smaller than a radial distance between a center of the cylinder and the shock-absorbing member mounted around the cylinder, the radial distance being measured prior to fitting the inner core around the cylinder.
 12. The compressor as set forth in claim 11, wherein the plurality of shock-absorbing protrusions are arranged in an axial direction of the cylinder.
 13. The compressor as set forth in claim 11, wherein the plurality of shock-absorbing protrusions are arranged in a circumferential direction of the cylinder.
 14. The compressor as set forth in claim 11, wherein the shock-absorbing protrusions have a ring shape.
 15. The compressor as set forth in claim 11, wherein the shock-absorbing protrusions extend outward from the outer circumferential wall of the cylinder.
 16. The compressor as set forth in claim 11, wherein the shock-absorbing protrusions are gradually tapered from the cylinder toward the inner core.
 17. The compressor as set forth in claim 11, wherein each of the shock-absorbing protrusions has a distal end pointed toward the inner core.
 18. A linear compressor comprising: a cylinder arranged in a hermetic container, the interior of the cylinder being filled with operating fluid; a piston to compress the operating fluid in the cylinder while being reciprocated in the cylinder; a stator having an inner core press fitted around the cylinder, an outer core located around the inner core, and a coil provided in the outer core; and a mover located between the inner core and the outer core and connected to the piston to be reciprocated along with the piston as it interacts with the stator, wherein a plurality of shock-absorbing protrusions protrude from an outer circumferential wall of the cylinder toward the inner core to be deformed as the inner core is press fitted around the cylinder.
 19. The compressor as set forth in claim 18, wherein the shock-absorbing protrusions extend outward from the outer circumferential wall of the cylinder.
 20. The compressor as set forth in claim 18, wherein the shock-absorbing protrusions are gradually tapered from the cylinder toward the inner core. 